The best source of information is the official SFM wiki.
There are also numerous video tutorials available on YouTube, including the official ones.
The up and down arrows take the playhead to the beginning and ending of a shot, respectively.
Audio should be in WAV format. And I recommend using a nice USB microphone for recording audio.
More models and props can be downloaded (subscribed) from the Steam Workshop. I was particularly interested in models with facial animations for lip-sync, and there are a number available there.
Attach a prop (e.g. a hat) to a character's head by locking it to the bip_head control in the character's animation set. Drag the character's bip_head control on to the hat's bip_head (or rootTransform) control, then select all of time in the Motion Editor (if it's not all green already), select the Body animation set of your prop and then under Procedural drag the Default control from left to right. You may need to adjust its position a little, especially if you used rootTransform because there was no bip_head.
Attach a prop to a character's hand by locking it to the weapon_bone under Unknown in the character's animation set. Similar to the above process.
In order to render 1080p videos, you need to start the program with the argument -sfm_resolution 1080 (either from your Steam library by right-clicking it and choosing Properties then SET LAUNCH OPTIONS... or by editing the desktop shortcut). This isn't recommended until you're ready to render, since working in 1080p makes things a little slow. Rendering 1080p videos takes a long time too, on my i7 desktop it took almost an hour and a half to render a one minute clip. If you're really adventurous you can render at 4K with -sfm_resolution 2160 but you'll need a decent computer a lot of time.
The basic process I go through to create videos (like the one below) is:
- launch Source Filmmaker
- name your session (or open an existing session)
- set the Framerate to 30 (although the default 24 is fine too)
- right-click the black part where it says "No Map Loaded!" and choose Load Map...
- for a quick overview of the maps, check here on the Team Fortress 2 wiki)
- you can move the camera around by holding down the mouse button where you'd just loaded a map (the viewport) while you use the keys WASD and ZX
- look in the categories player and survivors for good human models
- or click the down arrow on the right of the active camera button (below the viewport), click Change Scene Camera, and click New Camera.
- the same way that you added a new model in step 6
- if you want them to move with a character, make sure you lock them to that character (e.g. their weapon_bone or bip_head)
- when you are adding a clip to a track, any WAV files that are in the ...\steam\steamapps\common\sourcefilmmaker\game\usermod\sound file will show up