my 2 cent, build a beat first. download any free sample of kick,808 kick if lofi use that, snare, hihat, cymbals.
your beat gonna be dry and dull at this point. download a reverb/room vst to make your beat more alive.
build a bass line, (search for bass guitar/keyboard vst) just a simple pattern would do for now, you can alter it later on...this to add some groove with your existing beat.
now time for your main sound, i would try a synth vst 1st, slowly get some melodies that suit the bass and beat (drum).
when this is done, its time for tweaking/experimenting your main sound with anything.... oscillator, filter, distortion, bitcrusher, lfo, vibrato, tempo changing, sinewave change (all this are vst, you can google for free one) until you find your sound

lastly you can add any lofi vst to all of your sound created / or separately (drum 1 lofi vst) (bass another lofi vst and so on) until you satisfied.