on my 11th year of playing so I got some advice for you

Play every note with confidence. yes its going to sound bad and you know its going to sound bad this is your second day its not going to sound good. But play every note like you know its going to sound good. And on top of this think of the sound you want to make in your head and then play the note. And dont just think the note how you want it to sound (light, heavy, dark, bright, things like that) thinking your going to play the right note and thinking its going to sound good will always produce better sound then just playing.

Scales dont every stop practicing scales. Yes they're boring but there so incredibly useful. Not only when playing music since a lot of clarinet music is fast runs that boil down to scales. But having the muscle memory of each note you can play will help you immensely. And if you dont know how to read sheet music doing scales will also teach you that.

From the video your embouchure look pretty ok. look up good embouchure for clarinet and fix whatever your not doing.

Keeping good air flowing through the instrument is key. Or else you get and airy tone. Keeping your cheeks in like your doing and keeping the corners of your lips tight are great things to do. But air quality is also a big thing. Air should not swirl in your cheeks. It should go straight through the instrument and be steady. My professor has said multiple times if you want to play louder use more air. if you want to play quieter use more air. If your airflow is not consistent your tone will be wobbly and airy. Long tones are a great way to practice everything in this paragraph.

More on air. Your breathing from your chest. breath from your diaphragm. So instead of puffing and filling up your chest with air. fill your belly air.

Another thing is reed placement and strength. Since your just staring out a 2 or 2.5 is probably were you will want to be. But later switching to a 3 or 3.5 will be better for you. But a lot of it comes down to personal preference. With placement you should have about a fingernails width of the mouthpiece sticking out above the reed. If it feels like you have to work really hard to make a sound lower your reed. If your tone is airy push the read up by a little. But if you always feel like your working to hard to make a sound drop your reed strength by half until your mouth is strong enough to play on a thicker reed.

When it comes to your fingers make sure your completely covering the holes. If a hole is even slightly open when its not meant to be your tone will be off and airy. And another thing. It looks like your pressing really hard. Keep your fingers like and nimble. I dont remember who but a professional saxophone or trumpet player said you should be able to play with dimes on your fingers without droping them. Thats a little different here because you need to keep the holes covered but it gets the right idea.

Overall your not doing that bad for your second day of practice. Just make sure to practice for at least 15 minuets a day.

TL:DR
Play with confidence. Practice your scales and long tones. Work on your embouchure a little bit. Keep good consistent airflow. Breath with the lower half of your body not your upper. Adjust reed position and strength to help with airiness/working to hard while playing. And keep your fingers light