I agree with both things both people have said. Make sure the bit is mild and clear. The first few times he's bitted don't even mess with it. Just let him wear it and figure out how to hold it in his mouth. He's going to have a baby soft mouth and any messing you do with the bit should be in short sessions until his mouth hardens up.
Just put the bridle on and wait until he stops fussing then take it off. Repeat this maybe twice a day until he doesn't even think twice about it. Make sure you supervise him while he's wearing it so he doesn't get hooked on anything and there should be no food around for him to even think he can eat with a bit in his mouth.
Once he's comfortable wearing the bit without any fuss you can start training him to steer. Apply a tiny amount of pressure to one rein, I hold my hand on the horse's withers while I do it, so that when they turn they relieve their own pressure. If I hold my hand away I often find myself pulling more when they give. The moment he turns toward the pull release pressure and give him a little scratch, whatever he likes as a quick little 'good job'. Repeat this until he turns his head in both directions all the way touching his nose to his girth area with only a tiny amount of pressure on either rein.
Keep each session very short his mouth is going to be very soft!! With a baby mouth like this don't ever apply too much pressure, always start with the least amount and wait - if he doesn't notice the pressure slowly increase it, but if he feels the pressure just wait while he tries to figure out how to relieve it.
Make sure you are using an appropriate bit for starting a horse in. My preference in a french link snaffle with full cheeks with keepers. The full cheeks push the other side of his mouth in the direction you're pulling. It gives more clear cues. But NEVER leave a full cheek bit on a horse near anything he can get snagged on. If you don't have a full cheek use a tall D ring - but I prefer full cheeks with keepers as the keepers hold the bit in the correct position in the horse's mouth (so it's not just wiggling around).
Let me know if that's not clear enough :)