How to get started with a conference meeting with lib-jitsi-meet API

As I had a self hosted docker for jitsi server and I was unable to start conference with lib-jitsi-meet API.

ERROR TypeError: Cannot read properties of null (reading 'substr')
    at ue.resourceCreator (JitsiConference.js:292)
    at P.createRoom (xmpp.js:645)
    at ue._init (JitsiConference.js:342)
    at new ue (JitsiConference.js:133)
    at c.initJitsiConference (JitsiConnection.js:113)
    at AppComponent.createRoom (app.component.ts:81)
    at AppComponent.ngAfterViewInit (app.component.ts:116)
    at callHook (core.js:2573)
    at callHooks (core.js:2542)
    at executeInitAndCheckHooks (core.js:2493)
    at refreshView (core.js:9551)
    at renderComponentOrTemplate (core.js:9594)
    at tickRootContext (core.js:10825)
    at detectChangesInRootView (core.js:10850)
    at RootViewRef.detectChanges (core.js:22853)
    at ApplicationRef.tick (core.js:29572)
    at ApplicationRef._loadComponent (core.js:29610)
    at ApplicationRef.bootstrap (core.js:29546)
    at core.js:29245
    at Array.forEach (<anonymous>)
    at PlatformRef._moduleDoBootstrap (core.js:29245)
    at core.js:29215
    at ZoneDelegate.invoke (zone-evergreen.js:372)
    at Object.onInvoke (core.js:28591)
    at ZoneDelegate.invoke (zone-evergreen.js:371)
    at (zone-evergreen.js:134)
    at zone-evergreen.js:1276
    at ZoneDelegate.invokeTask (zone-evergreen.js:406)
    at Object.onInvokeTask (core.js:28578)
    at ZoneDelegate.invokeTask (zone-evergreen.js:405)
    at Zone.runTask (zone-evergreen.js:178)
    at drainMicroTaskQueue (zone-evergreen.js:582)

I was using an angular project and followed this example:
Basic lib-jitsi-meet Angular Implementation · GitHub.

Is there a better way to use lib-jitsi-meet API(low level) or any examples meeting my requirements where I will also be able to control number of participants?

The lib-jitsi-meet example is here