How do you set custom weapon loadouts for a map you are making so that players who download the map will start with the loadout you want for them? I know you can do this in the game options for custom games, but the options are not the same for Forge..
Weapon loadouts are not specific to maps, they are specific to gametypes. This means that you can't have set loadouts 'built in' to the map itself, you must make an accompanying gametype and recommend it to be downloaded along with the map file. On FH there is a field in the map database input form to provide a link to accompanying gametypes, though it's worth making visible mention of it in the main body of the post just so people don't miss it. If you want the gametype to be downloaded along with the map when just browsing/searching Bungie.net, you should consider putting the gametype and map in a fileset together. You could also include mention of the gametype in the map file description, for example putting 'For use with so-and-so gametype.'
How do you put them in a fileset? Does that mean that when someone downloads the map, they automatically dload the gametype too? Or does it just mean that when they click on the link they see both of them there?
When you log in to Bungie.net and go to your fileshare, there's an option which says 'add to fileset' under each file where it normally has the download link. That would be awesome, but sadly not. I wish Bungie had implemented this as a feature, though I can understand why they were wary of having any kind of forced download. Pretty much this, I think it appears at the side of the page, there's a box called 'other files in this fileset' or something similar. Honestly I think it could be a bit more prominent, like when you click on a file that's in a fileset, the file you clicked on shows just as normal but all the others are directly below it in a list, just as visible as the main file itself. However, what we have still works quite well for encouraging people to download accompanying gametypes etc. EDIT: Just checked using some of my own files and it appears that it's changed since I last checked back in H3. Now when you navigate to a file, there's an alternate tab next to the comments section where other files in that fileset will appear. Whilst this makes the other files more visible once that tab is clicked, it requires the person browsing to check whether the file is in a set rather than just being shown directly, not sure how fond I am of that choice tbh, but it's still useful.