i have a trek pdx that i want to convert from a 24 to an 8 speed.

https://www.trekbikes.com/us/en/bikes/urban/pdx/pdx/

i have found a crank set that i think im going to buy and i thought i would put it up here to see what people thought.

https://www.vueltausa.com/components/...set-black.html

I am not very mechanically skilled yet so i have a few questions. will i need a new bottom bracket or any other drive train parts to make that crank work?

will this crank require a new chain and if so will that chain work with my 8 speed cassette?

Thank you for your input!

Your chain will work. That crank calls for a 108mm square taper bottom bracket. I'm sure you can find out what yours has somewhere on line. You will need a crank puller to remove your old crank.

A triple to a single means the Middle chainring remains,
Its in the right chainline.

consider just making the middle ring bigger ,
and remove or ignore the inner and outer..

I have done that on a couple of bikes. I looked at his current crank and don't know if his chain rings are replaceable. There may be bolts under the chain guard.

I agree I have a feeling the rings are riveted together. I think when the OP orders the crankset he should just order the 108 BB, it is only $10