Calipers installation

Welcome to 2CarPros. Which caps are you referring to? There can be caps on the bleeder valves to keep them clean, those you just pop off when you need to bleed the brakes, then put them back on when finished. Most also come with a plug in the fluid line port that you remove before installation. That would be the green item in the picture. Or is it something else entirely?

The green cap pulls out and your brake fluid line bolts there.

As for the shock/strut, you always replace them in pairs to avoid any handling issues. If you are talking about the rear shocks, they are not that hard if you don't live in the rust belt states. You jack up the back end and put a jack stand under each side of the suspension then remove the wheels. Then you have 2 bolts that secure each shock. If you are in a salt/rust state removing them can be very hard as the rust will bond the pieces together like a weld. Either way you remove the lower bolt then the upper. Install the new ones and apply a thing coat of grease or anti-seize to the bolts to make them easy to remove the next time.

If you mean the front struts, unless you have the proper tools to compress the springs and R&R the struts I would let a shop do it, unless you opt for a quick-strut, those are a new strut, spring, and upper mount all together, they are more expensive but much easier to deal with as you don't need to fight with the spring. If you are replacing struts keep in mind you will need an alignment after they are installed.