Lens adapters for Canon Rebel Xsi

[oldcameraman]

HI,
Have Canon Xsi and want to fit old camera lenses from a Pentax 1000K and ultimately an old Canon A1.

See adapters with and without 'Confirmation' but they all look like there are 'Gotcha's' for a novice.

Can someone elaborate on whether an adapter with the 'confirmation' enable use of the Pentax 1000 K lenses that I have and if the 'gotchas' are such that it would be a constructive thing and not just frustrating?

Thank in advance!

OLD cameraman