General advice: interactive webpage with lists to generate db querys [on hold]

I would like some general advice please on a small project I would like to develop. I'm quite new to web development and would like some general strawman pointers from the outset so I can best focus the solution.. It's looking a bit daunting at the moment :)

Basically, I have a mongodb with multiple entries in the same collection. I would like to create a webpage that generates a dropdown box with a list that is sourced from a database query - for example:

for post in db.find({'type': "server"}):
name_list.append(post['name'])

'print name_list' would give [server1, server2, server3]

Where the user can then select the 'name' and then this option is used in another db query to generate another dropdown box that would then in turn be the source for another database query and would eventually print out the final queried result to the webpage for the user to see.

I'm keen on perhaps using flask and putting in some nice css styling but I'm quite unsure how to have this kind of interactivity.

Again, please, I'm not looking for a coded solution but rather just some pointers on the next best steps.

Thank you.