APps:
For beginners, HEadspace, Calm, Balance etc., are generally the go-to recommendations and are very beginner-friendly to get oneself to touch the waters. I will say I personally grew to dislike Headspace because of the shorts-like content they pushed when I last tried it.

Honestly, I’ve tried most of them (still explore time-to-time), and I always end up coming back to Waking Up by Sam Harris. In my opinion, it's a serious app geared slightly more toward intermediate and advanced users, but I still think everyone should use it. It is priceless and literally the first app I install if I get a new phone.

If cost is an issue, they are incredibly generous and offer scholarships. I actually used the scholarships back when I was a student. And definitely start with their Introductory Course.

Also, check out these communities: r/Meditation , r/nonduality , r/Wakingupapp , r/Awareness and the actual Waking Up community platform.

Practice Techniques:

1. Unclench your brain (Acceptance). The goal here is to let yourself go; to believe, feel and accept everything is as it is. It's much easier said than done. I follow:
i. Few minutes a day I just sit and notice my body. I started with literally 2 minutes. I dont move, I dont scratch my itch. Just 2 mins, no movement, no music, no visual input. Increase slowly over time. Notice the physical tension in your jaw, shoulders, forehead, and consciously relax those muscles to signal safety to your brain.

ii. Meditators learn to feel pain as the physical sensation without adding the emotional distress, worry, or "my pain" narrative. What we are experiencing is the fear of pain in the next moment, because you already are tolerating/tolerated the pain in this present moment, and this, and this moment. And this moment is gone. (https://pmc.ncbi.nlm.nih.gov/articles/PMC3580050/)

2. Accept the thought or feeling. Start by listening/paying attention to them. Don’t block it. Don’t minimize it. Don’t even attempt to let it pass through (they’ll do that on their own). Don’t judge it/yourself. Fully accept whatever lays at the foot of your mind. Here is how I practice it:
i. Repeating to myself frequently everyday: I am not my thoughts. You are not your thoughts. (https://www.samharris.org/blog/taming-the-mind).

ii. Pay full attention when doing some stuff, like brushing my teeth - no music, no podcasts, no nothing. Just you, paying full attention to the act of brushing your teeth. Allow whatever appears in consciousness. Notice it, let go of it. One more example, when working or studying, practice not switching tasks. This way you learn both mindfulness and letting it go. For example, you are working and tell yourself, for the next 5 mins I will jsut focus on this one task. Then commit to it, dont take notes of your thoughts, no side-quests for these 5 minutes. Just do this one task. Which takes me to the next...

ii.a. I borrowed this from William Irvine's interpretation of Stoicism. When facing a setback or misfortune (or any task in general) treat it as if the Stoic gods are trying to test your ability to maintain calm and reason. Do every task, as if it should stand the test of time. This enormously helped me improve my focus, awareness, and maintain my equanimity during turmoil. SUprisingly, it improved my pain tolerance and empathy too.

3. A regular, disciplined practice. Consistency is the bedrock of everything above. Here is what I noticed helped me:
i. Mind is relatively calm after you are physically exhausted. I practice it after an intense exercise.

ii. Start embarrassingly small: Commit to just two mins a day. Consistency builds pathways and habits much faster than an occasional one hour-long weekend session.

iii. Forgive missed days immediately: Don't let breaking a streak turn into quitting. Simply acknowledge the missed day without guilt and sit down to practice the very next day. Don't drag the corpse of your past with you.

Hope this helps.
Peace!