Hair regimens are so personal BUT, I can help you get started!
The key to a good regi for me are 4 main steps:
Cleansing
Conditioning
Moisturizing & Sealing (counts as one step to me)
Protein/Strengthening
Your hair will tell you how often to do each of those things.
Low manipulation styling and tying the hair down at night will help you retain what you grow. Seems like you're doing well because your hair is APL-BSL now.
First, research the herbs to see which ones you'd like to try for each step. Then determine HOW you want to use them (hair mask, oil, tea, gloss and even, internally). Keep notes because some of them do almost the same things but one might work better for you than another. Try not to get discouraged if some don't work well for you. Sometimes, it could just be the way you're using it might be too potent (or not potent enough) or you may just have to substitute another similar herb.
A good way to start is by just replacing the steps you're already doing with Ayurvedic ingredients. I tried to do that using pre-made/OTC Ayurvedic products but I found that to be ineffective. Either the product had too many other things in it that weren't good for my hair (Vatika and Vaadi) or the Black owned companies I tried to use went out of business, had VERY slow shipping times (like 30-90 days) or customer service was not consistent. For me, it was easier to just buy my own herbs and mix my own product. I prefer to use glosses. It is as simple as just adding the Ayurvedic ingredients to cheapie conditioners to create whatever step I'm trying to do (cleanse, condition, protein, M&S). I mix them up approx. once a month, for all of my steps, and use them like pre-made/OTC products.
When I first started, I bought a bunch of the powders and did masks with them. I quickly learned that masks aren't my cup of tea. But I really wanted the benefits from the herbs. So then I started doing glosses and cold infusing the powders into oils to use that way. Using infused oil is another easy way to incorporate Ayurveda into a regi. I use one to oil my scalp that's infused with herbs good for growth and a different one infused with conditioning herbs to seal my hair. There are different methods for infusing oil, whichever one you prefer will be up to you.
I also started using the powders to make teas to spray or pour onto my hair. Then I started buying some of the herbs in tact, instead of in powder form and infusing them into oils and making teas for when my hair is braided with extensions.
For some other ladies, they continue using the non-Ayurvedic products they always use and just do an Ayurvedic mask regularly (weekly, biweekly or monthly) for its benefits. I kinda see it like when someone is wanting to incorporate a raw diet. Some may find it beneficial to just be 50-80% raw and others will want to be 100%. It's all up to you!
As for purchasing, I'm a KISS lady so I primarily purchase from Amazon. Some sellers even have herbal packs and mixes already put together! I've purchased those too for hair oil infusions and I gave one to my BFF/sister to use as a cleansing tea.
There are so many options for you to incorporate Ayurveda into your hair regi!