OK first vid is good, just pull fuse for each of the new items you installed and see if it drops to less than 1 amp as in the vid then you will know then.
To test your Alt reconnect terminal on battery MAKE SURE YOUR METER is back to measure Volts, start car hold revs up not to fast and measure voltage across bat should rise to about 14.1V if it does Alt is OK
Make sure the probe plug is moved from Amp to Volts if you don't the instant you measure volts the meter will be destroyed.