Martin from LetsGoChannelSurfing has a bunch of videos on installing an upgraded solar system to get you started.
Easiest place to start is replacing the current solar controller with a Victron Energy SmartSolar MPPT 100 volt 50 amp controller. This should work up to 500 watts of solar from most solar panels later on. Read the VE instructions. There is a specific sequence of moving wires from old controller to new VE 100/50 that needs to be followed. That step took me 2 hours in the cave to complete.
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The next step is to ensure the wiring from the new VE solar controller to the house battery will be “beefy” enough to handle your new panels output. You may need to run new heavier wiring from your VE controller to your house batteries. Good idea to install a resettable breaker near the battery for protection.
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The run from my controller to the house battery bank was about 10 feet, easy to reach and took 1 hour to do.
The last step is actually upgrading the panel itself. The key points to consider are panel size fitting your space, getting mounting brackets to attach panel to the roof SS tubing, ensuring wiring size from panel to controller will handle new panels output and installing MC4 connectors on the existing wires to connect to the MC4 connectors on the new panel. Doing this required a second person to help me move the new panel onto the roof after removing the old panel. Total time was about 3 hours.
Lots and lots of online videos by Martin and others to walk you through every single step of this process.