Hi Arnied,
Its always easier if you have someone who knows what their doing to show you how.
What kind of suit have you got? Neoprene, compressed neoprene or tri-laminate (shell suit).
Cuff or auto shoulder dump?
One of the first things you need to do is sort out how much ballast weight you need.
You need a diver assistant.
In the UK we use 50 bar as the safety reserve and plan to arrive on the surface with that amount. You have a simular reserve but you express it in psi.
Fully kitted up with a your single or twins tanks on safety reserve, establish what weight you need to sink on exhale, advice is find the minimum and add 4lb. Be sure you are in an upright position and fully empty your suit and bcd of air. N.B. salt water is more buoyant than fresh. If in future you increase your underclothing or change tank size you may have to adjust your ballast. I think a thick pullover for a large man is about 4lb extra buoyancy. The same size tanks does not always weigh the same.
Everyone warns about foot inversion getting loaded with air in your feet and on the surface being unable to right one-self.
Get in a swimming pool fully kitted up with an assistant standing by, grab the ladder in the deep end and with your head down fill your boots then floating feet first let go and learn to right yourself. You will probably struggle and may need assistance the first couple of times, but you will get it right.
The squeeze from compressed neoprene suits can give you large hicky type burns if you don't work some air into the legs even on shallow dives to 6m.
Shell suits are more forgiving and you don't need so much to offset squeeze.
Most club divers over here dive with single tanks and don't practice as much as they should, so they are advised to use only the suit when underwater to control their buoyancy, that way there is only one control to bother with. Some experienced dry suit divers, just put enough air in the suit to avoid squeeze and control buoyancy with the bcd, ascending from a deep dive they have to dump from two places, its not a problem.
If you have a shoulder auto dump, open it fully at the beginning of the dive and leave it open. Though its supposed to be automatic you will need to raise your shoulder to dump air if you swim in a horizontal trim. Cuff dump is pretty simple lift your arm.
The rest of the game is about retaining neutral buoyancy, its comes with practice. Add air slowly a touch at a time and pause, dump air early, a little at a time.
A sticking inflation valve can happen to anyone. If it happens to you, open your neck seal and disconnect your inflator hose fast.
A flooded dry suit may be cold but water weighs nothing in water.
Harry Rat
has some good articles and exercises for building up good buoyancy control. Take it easy, dive with a buddy and give yourself chance to get plenty of shallow dives practice, at least the first 4 dives 6 to 10m max depth, next 6 max depth 20m. Most of us here do 25 to 35 non deco dives max depth 20m to get used to a dry suit before doing more adventurous diving.