Usually people aim for 10-12 reps each set (which means that after that you drop down from exhaustion, you should gradually make the exercises harder so you have a max of 10-12 reps per set).

1-5 is usually to build strength (basically, when you add weight or leverage to make your exercise harder, you will be able to do 1-6, keep training until you can do 12-15 reps and then make the exercise harder again).

50 reps is actually pretty much and you will be building endurance. Which isn't bad, but not what most people aim for (HIIT burns more calories anyway and the muscle you build will even burn more as muscle is the most metabolic inefficient tissue of the human body).

I used a small backpack that i filled with bottles water or sand, but its pretty inconvenient for push-ups etc (it strains your back). So i suggest adding difficulty to your exercises by adding leverage (putting your feet up an elevated platform), performing your exercises on a unstable platform or by using only one limb instead of two.

If a certain exercise is very hard (e.g.: i had some trouble with wide pull ups at the start, do negatives (in this case: jump up to the bar so you don't have to pull yourselves up and lower yourself as slow as possible.

I dont know what you read already on this topic, but there are multiple good guides:

'never gymless'
'you are your own gym'
'overcoming gravity'
...