I’ve had my bike one day and lost on of my fork lock switch caps. Appears to be a Suntour (guessing as it looks the same as ones I’ve seen online). They come in different sizes- XCR, XCT, XCM, EPICON. Does anyone know which ones fit. 2020 Bolt X?
The blue one is just a lock. It is meant for climbing hills or very smooth roads. It's honestly probably best to leave it alone (unlocked) on cheap bikes because they have no blow off valve, or means of accidentally relieving pressure of an impact when you forget to unlock it after a climb. You can easily damage the mechanism if you hit big bumps or potholes with it on.
The other one is a pre-load. It's not technically correct to say it's for weight, as the proper adjustment for weight is spring rate (How heavy/stiff the spring is naturally). For a higher end fork, you always start by installing the right spring for the rider, then adjust the rest to suit. When you max out the preload on a cheap spring to compensate for a heavier rider, all you are really doing is pre-compressing the spring and reducing your available travel and sensitivity - therefore making the fork much less effective. But it can reduce the sag (it's intended purpose) and minimize some of the spongy/bouncy feeling, so it is used as a band-aid fix in lieu of installing a properly rated spring. If you can actually get the right spring in there first however, your suspension will feel miles better than just cranking up a light spring.
And on a modern general use fork like the one shown, there is often only a spring on one side, and a basic friction lock on the other. Hence the derogatory term "pogo stick" you'll often see on forums like this. Premium and heavier forks used for downhill and jumping will likely still have two full springs (or adjustable with air pressure), and added damping and rebound on one side only. Many newer midrange and premium lightweight forks will still only use one spring, but the other side is a much more complex air/hydraulic compression and rebound damping system, and a 'lockout' system that has failsafe valves built in to prevent damage, and a wider range of adjustability. You can usually tell these systems as the adjustment valves are different, and many have the additional rebound adjustment valves at the bottom of the shock by the axle.