Right angle and flexshaft attachments are both great adds to Dremel rotaty tool.
Sometimes you just need them both in same package.
Step 1: This Is Easier Than You Tought.
What you need.
Of course both of those attachments. And a washer in diameter 13mm inner / 24mm outer hole. ( 1" = 25.4mm)
And both of those silver coloured collets wich came with the right angle- or flexshaft attachment.
Those should include to the attachments.
Step 2: Insert the Washer.
Mount one "silvery" collet to dremel, and other to the flexshaft.
Watch the video how to insert the washer.
Now you have tiny and very handy "angle grinder" for cutting, or drill that fits to tight spots too.