It can be a little disconcerting when first starting with CircuitStudio, it can appear there are no libraries. However there are really lots of components on hand. When first installed there will be a couple of libraries containing basic components, "Miscellaneous Devices.IntLib" and "Miscellaneous Connectors.IntLib". There is also the Online Vault accessed under File > Vault Explorer. Downloadable libraries are available from https://designcontent.live.altium.com/ and you can even import Eagle libraries using File > Import (as with any CAD translation process always check the results so you don't get caught out).