If you want to finish the Hideout Helm stage, you're going to need to become real good friends with Snide. You do that by collecting all his blueprints, scattered throughout the game. Each blueprint is guarded by a guy that yell's "Splat". He has some funky hair that changes color to reveal which Kong's blueprint he is guarding.
Finding blueprints, then, is relatively easy. Just search through a stage long enough, and you'll find where it is hidden. None of the guards are really all that hard to find. Make sure that once you find a guard who's packing a blueprint, you come back immediately with the corresponding Kong. This should be a priority. It will save you a lot of backtracking, and a lot of grief.
There are also guardians in the main area that serves as the doorway to all the levels, DK Isles. These guys have a tendency to hide in crates, or otherwise make themselves distant. You can still find them.
Each blueprint you bring back to Snide earns you a golden banana. For this reason, I'm only going to tell you where the guardians are located in the sections that fall under the 'Golden Bananas' heading. Rest assured, eventually you will find instructions on how to get all 201 golden bananas in one of those categories. It would just be a waste to outline all the directions twice.
One last thing: if you're looking for Donkey Kong's banana, it is in the entrance to Hideout Helm. Once you have gotten that blueprint, you should already have the others. Now you can go to Snide and get your reward, and also access the final stage. Good luck!
NEXT: Banana Fairies