@chongjasmine...
You didn't give your location; to judge from using '$', I guess you're not in the UK. That's not a problem, of course, but some replies may not be relevant or applicable. Where are you, please..?
The ideal way to learn from the very start is with a few lessons, face to face, with a competent teacher. I understand that this may not be possible or practical, but it's still the best recommendation.
Having said that, it's not necessary to start 'strumming' at all. Get the chord shape right ('D' is, perhaps, the easiest...), and lightly brush the strings, from the bottom string (the low 'E' nearest your head...) to the top string. As you brush, listen to each string, and practice getting the fretted strings sounding clearly. Remove the left hand from the strings, fret the chord again and brush again. Do this for a while (not long; just a few minutes...), then give your hands a rest. Choose another chord ('A' is fine, but 'E' may be easier; it doesn't really matter too much for now...), and repeat the light, slow brushing from string to string, listening to be sure that each string is sounding clearly. A few minutes, and rest.
As a rule, it's best to practice in short, regular sessions, rather than long ones. Two 10-minute sessions, each and every day, are much better than one whole hour once a week. 'Little and often' is the key.
Playing a guitar does not have to mean playing every string. It's not necessary to 'strum' all 6 strings, all the time (although it is often done, it's not a 'rule'...). You can lightly strum, for a 'D' chord, for instance, only the top 4 strings. With a 'D' chord, the bottom string (the low 'E'...) is not, harmonically, part of the chord, and should not be played, or muted so as not to sound. You will have difficulties with this, and other chords, if you're beginning, so don't try to do things that you think are right; do only the things that will make you a better player. This will involve patience, and some concentration on your part. It seems, at first, as if no progress is being made, but be assured: every guitarist started out in exactly the same way. Go slowly, very slowly; that's the fastest way to get to the destination.
Hope this helps; others may have more advice or tips.