Scratch is an object-oriented programming interface that uses blocks as scripts. In this Instructable, I will teach you the basic elements of Scratch. For more information, to view uploaded Scratch projects, and to download the latest version of Scratch, visit scratch.mit.edu.
Step 1: Area Overview
Scratch has a few main areas. The first area is the palette. The second is where you drag scripting blocs and edit everything. The third area is the stage, where you view the action. In the fourth area, you select a sprite to work on and view basic information. The top area holds menus and toolbars.
Step 2: Palette
This is the palette area. At the top, you can select whether you want to view blocks of various natures, signified by what the button says. (wink.) Below, you can drag blocks to the scripting area to make sprites to various things. Note: puzzle piece-shaped things mean they go above/below another block. Round or ovaloid things (usually with text inside them) accept numbers/values. You can either drag an ovaloid block into them or type a number. If there is a pulldown menu, you can also choose from that. Square areas accept text, numbers, or ovaloid blocks. Pointy areas accept things that are true or not true. For example, "A=B" or "touching mouse-pointer" are a few options. Checkboxes allow its value to be shown on the stage along with a label. Also, if you right-click on any block, whether in the palette or in the scripting area, if you click help, a window will come up (in Scratch) that explains what that particular block does.
Step 3: Scripting Area
The second area has three sections, the scripts section, the costumes (or, if the Stage is selected, backgrounds) section, and the sounds section. Above the tabs is an area where you can rename the sprite, change the way it rotates, see where it is, which way it's facing, and set if it's draggable or not on the website once you upload it.
Step 4: Stage and Sprite Areas
In the stage area, you have omniscience. You can see what sprites are doing, where they are, view the location of your mouse relative to the center of the stage (0,0), start and stop the program, resize sprites, delete and duplicate sprites, export sprites, even capture a screen region to make a new sprite or costume or save a picture of the stage. Most of this you do with right-clicking (or ctrl-clicking with a one-button mouse). (Tip: to make a new costume from a screen region, right-click on a sprite. To make a new sprite from a screen region, right-click on the stage. It will automatically make the outside white it sees transparent.*) The green flag and stop signs are used to start and stop the program. (When it is uploaded to the website, it will automatically "click" the green flag button when its page loads.)
In the area below that, you can paint or import a new sprite, or, if you need inspiration, just import a random sprite! You can select a sprite to work on and view its name. You can do basic actions to it in the contextual menu (what you get if you right-click). To view the number of scripts it has, mouse over it for a moment.
*For example, if you captured the area in the note around the cat, you'd just get the cat, not the white around it. This can be useful but sometimes very annoying.
Step 5: Menus
(Pre-script: the pictures are in order by where they are in Scratch, not the order I present them in.)
The image notes speak for themselves, but here we go anyway. in the far upper right corner, you have the option of viewing your project in presentation mode, small stage mode, or large stage mode. Presentation mode is good for showing your project to people (e.g. projected at an exposition). However, at time of publication, you cannot run this off the internet, so you must have the project and Scratch on your computer to do this. Small stage is good for coding so you have lots of space to work with and large stage is the normal mode.
In the top middle is the toolbar. Holding down shift while using any of these keeps them active instead of just going back to the cursor tool when you click and it does its stuff. The first is for duplicating, the second is for deleting, the third enlarging, and the fourth is for shrinking. they all work for sprites and the first two also work for scripts.
I will now attempt to go over the menus. everything that it is obvious what does I will not mention. The first three buttons let you choose your language, and save (cmd-S or ctrl-S works here, too) or upload your project to scratch.mit.edu. In the File menu, the only thing of interest is Project Notes... This lets you edit your project notes. When uploaded to the site, these will appear to the right and slightly down from the top of your project. Warning: most people don't always read these, so it's best to put instructions in-game. The Edit menu is very interesting. Undelete (cmd-Z and ctrl-Z, folks!) ONLY undeletes the last script you deleted. IT WILL NOT UNDO ANYTHING ELSE! Single stepping just flashes the block it's on at the moment and goes one block at a time. Very slow, but useful for finding out what's going wrong. In Set Single Stepping... you can choose to go in turbo speed (obvious what this is), normal, flash blocks fast (like single stepping only faster), or flash blocks slow (normal single stepping). The Show Motor Blocks command is for use with Lego WeDo, which is compatible with Scratch. I don't own any, so I cant explain them. Almost done! Help Page... and Help Screens... take you to the help on the website. About Scratch... shows info about this version in a popup.
Step 6: Wrapping Up
I think this is it! This is my first Instructable, so if there's anything I did wrong just tell me and don't try to bash my brains out with a lemon-wrapped gold brick, for all you hoopy strags. (About five of you will get this joke.)
...and they all lived happily ever after.
...(It wasn't a Thursday.)