It is good to hear you are starting this. It will not affect weight loss, however, it will improve your health. In reality, I think that is what you are interested in improving.

Anyway, here are my suggestions and disclaimers. I am not a personal trainer. The vast majority of what I know is based on n=1 experiments and most of those were initiated in one of 2 ways. First was when I saw someone at the gym who looked or performed in a way I wanted to look or perform, I tried to mimic what they did. Second, I heard or read something from someone claiming to be an expert so I tried it.

Step one is lift heavy. This means heavy for you. If you can easily do 3 set of 10 reps, you need to increase the weight. Ideally, be at a weight where you can't quite get the total number of reps you are trying to get. That number may vary. Minimum of 3 sets. Max of 5. The number of reps per set may vary. I find personally going below 6 is not as effective and going over 12, the same. These numbers may vary depending on the exercise/muscle being worked.

For instance, if you were doing 5 sets of 12 on leg press, you would, in reality, like to get to a weight where you are really doing 4 sets of 12 and a set of 9 or 10 because you just can't get the last couple. Legs are an area where I lean toward higher reps because logically, they are better suited for it. Just think about the fact they are used for walking, standing and running which are all things that take many repeated motions.

On the other hand, bicep curls may be one where you do fewer reps per set because most things you do with those muscles tend to be just a few at a time in the real world.

Ease in. Especially the first time, you may feel like you can do more, but stop. You do not want to overdo it which can lead to not doing it again. If there is no soreness at all afterwards, then, by all means, do more the next time.

The first few times should primarily focus on getting comfortable with the movements and making sure you have good form. Bad form causes injury. If you can't do it with good form, lower the weight until you can. When talking about the above and lifting heavy, I mean lift as heavy as you can with good form.

Consistency is key. Personally, that means I work out M-F every week. If I were to only work out 3 days a week, I would skip Monday and figure I would still be able to get 3 days in, then I would skip Tuesday figuring I still had 3 days. Then something would end up happening and I would miss at least once more and within a few weeks I wouldn't go working out at all.

Hope this is helpful. Good luck.