I would start running through the official docs first in this order;
#1 https://github.com/ytti/oxidized#installation
#2 https://github.com/librenms/librenms/blob/master/doc/Extensions/Oxidized.md
(remember to create a user in librenms for oxidized where you will get the X-Auth-Token in the libre GUI)
Then check advanced configuration here for device type mapping etc:
#3 https://github.com/ytti/oxidized/blob/master/docs/Configuration.md
Then if you get stuck check this complete guide which seems pretty good #4 https://techstat.net/how-to-integrate-oxidized-into-librenms/ or post on here