I am a bit of overweight guy and I don't know anything about lifting and fitness. I can't go for strength due to very weak joints. (no loaded squats) I would like to go for body building or hypertrophy training. Some pointers, tutorials and links to resources are welcome.
As equipment goes I only have resistance bands, a bicycle and an outdoor gym.
Also how important is a diet in keeping myself fit?
You need both. Just dieting will lose muscle mass as well as fat, resulting in lower metabolism. You'll then gain weight again, diet again, losing even more muscle mass. Years of this will leave you in a really bad state. Lift weights, and eat a healthy diet that fuels your muscle.
I think op should be asking "how do I weight train as an overweight person with bad knees?"
Obviously physical activities burn calories that could otherwise become fat. But no sedentary overweight person is going to suddenly start training for a half marathon and stick with it long enough to get results when your goal is to just lose weight. And that's ignoring the very high risk of injury from making such a move. It's a problem of adherence, not physics.
I'd recommend 'convict conditioning' by Paul Wade. Free pdf / epub is easy enough to find with a quick search. The book does a better job of describing itself than i can, but basically it details 6 "power moves" (push up, squat, etc) and 10 steps within each move-set, 1 being the easiest/introductory exercise and 10 being the 'mastery' of the movement. I.e for push ups- step 1 is wall push ups and step 10 is one armed push ups.
Im actually gonna try to double down on this recommendation after re-reading that you also have joint issues. Step 1 of each of the 'big 6' is picked with this issue in mind and tend to describe them as good "therapy" excercises for people recovering from injury/surgery/illness/etc.
I'm not saying this guarantees you'll be able to work up to one armed push ups (im still mountains away from that feat myself) but if regaining joint strength/durability is one of your main areas of focus, id very strongly recommend at least skimming through the 1st step or 2 in each of the big 6.
It's also got a chapter on self coaching, which ive found very useful to revisit every now and then
I was overweight for a while. I was trying to find a program to get me back into shape. I came across the Shaun T videos. T25 and Max 30. I couldn't do the normal program because of my knees and back but they have modified workouts for them. I lost a ton of weight and gained muscle. It was very tough and 5 days a week or workout but it's only 30 minutes at most. To mirror what other people have already said, your diet is the biggest factor, that has to take priority as well. You can do it though!
Not sure what will work for you, but I lost 40lbs by riding my bike 12 hours per week, and cutting processed sugar from my diet.
Now I've moved on to hypertrophy lifting with Caroline Girvan 5 days per week, and riding bike 6-8 hours per week. I've gained 5 lbs back, but its muscle and is fine.
Also, oatmeal with a fruit (either blueberries, strawberries, banana, or raspberries) in it every morning for breakfast