It'll be hard to figure out where to begin and what to do as you are correct about the many things out there, as well as conflicting advice. Dont get overwhelmed with all the things you can use either. Start off slow and gradually get there. LEARN how exercises are done, how your body responds, doesn't, and what works for you.
A website that is great for information is
www.exrx.net it is used widely across the fitness industry and by professionals as well.
Books that are good, are book by Human Kinetics, NSCA books as well as ACSM books.
When you ask the guy at the gym to make you a program, assuming he is a personal trainer, ask him his credentials. Sounds like an extra step, but there are GREAT trainers, and then ones who have a one week training and seem to think they have it all down.
Look for a person to at LEAST have a degree in Athletic Training, Exercise Science, Physiology, and even better, certified from the ACSM, NSCA, or CSCS. These are your top 3 certifications in the fitness industry.
If you look for a good job, you can't get by with less. No one will hire someone with an ACE certification, NETA, or standard YMCA CPT. It isn't enough.
A TRUE program designed is called a periodization program and is very detailed. If you have any one of those certifications or a degree in those areas above as I listed, you will have written one for a class. They normally cost money, but they are specific to the person.
For instance, A rower, a basketball player, a bodybuilder, etc etc. The list can go on for all sports. It is divided into micro/meso/macro cycles and charted out week by week for 52 week. Strength phases, hypertrophy phases, power phases and recovery phases. Again not all will be included for each person, as certain individuals wont need as many weeks as others on key areas.
The main thing, is that it will take time to get use too, and you will never know it all, and cant. Even those of us who spent 4yrs getting degrees in this area still have many things to learn as science progresses.
If you happen to ask the guy at the gym to make you a plan, post it on here and have us look at it and tell you what is good and isn't good about it, or what could be improved.
Just because a person lifts a weight doesn't mean they are capable of helping others. There are many times when someone will tell you to do exactly what they are doing.
Its like people trying to do Ronnie Colemans workout or Jays. You aren't Ronnie or Jay, and you cant do what they do.
Your body is unique, and what works for the guy at the gym may not work for you, or vice versa.
Last but not least, you will have to get the proper rest, & nutrition
Now 300 physique, if you mean you want to weigh that, then good luck without the juice. 300 is Pro bodybuilding physique unless your just fat. That's a different category of the 300 club
If you mean benching 300 or something, that's a different story.
