There are many factors in adressing a client’s needs. It’s simply impossible to narrow it down to a simple forum reply.
As Chris said, a Par-Q, a Postural Analysis, a Kinetic Chain Assessment are mandatory for proper individualization of the training plan.
Record all measurements, body comp, Resting Metabolic Rate.
Get detailed info on their current diet, workouts, supplementation, training experience, and goals/concerns.
Always start a client with an Anatomical Adaptation phase, following a higher rep, circuit type training for the first few weeks. Never start someone with 0 experience on a Strength routine. After the AA phase, follow it up with additional Body Comp work if needed. Following it up with a Hypertrophy phase, a MxS phase, and finishing off with a shorter Conversion to Power phase will ensure great results in terms of body comp, muscle gains, and Strength. The conversion to power phase will improve the Rate Of Force Development and is crucial if you’re preparing for a sport, but there are many many variations of this Periodization plan - and in the end you may not even choose to periodize in this way, but do make sure you always start a new client on an AA phase to prepare them for the following Maximum Strength phases.
Periodizing the loading Parameters is a great way to prevent overtraining and to allow full recovery of the CNS after very intense training. An example with this would be starting with 5 days of Low , followed by 5 days Medium, and topping off with 5 days High loading parameters; then come back down to Low-Medium and finish off with 3 five day microcycles with high intensity. At this point you might switch to a different type training (MxS, Hypertrophy, Power, Endurance…) at a low intensity. The key is to progressively increase the load and allow both the muscles and the CNS to recover maximally.
Personally I would progress from exercises requiring little stabilization such as a Chest Press machine to strengthen the main working muscle, before moving on to more challenging free weights.
A diet is essential if you’re looking for results in terms of body comp.