These are basic, but will get you started:

Herbal Antivirals Heal Yourself Faster https://www.scribd.com/document/528776124/Herbal-Antivirals-Heal-Yourself-Faster-Cheaper-and-Safer-Your-a-Z-Guide-to-Choosing-Preparing-and-Using-the-Most-Effective-Natural-Antiviral-Herbs

Herbal Antivirals - How Herbal Medicine Can Heal You Naturally https://www.scribd.com/document/472400314/Herbal-Antivirals-How-Herbal-Medicine-Can-Heal-You-Naturally-Little-Known-Ways-Beginners-Can-Use-Herbal-Remedies-and-Herbalism-to-Build-Their-Own-A

Herbal Antibiotics and Antivirals https://www.scribd.com/document/380227587/Herbal-Antibiotics-and-Antivirals-Stop-Making-Them-Rich-Ditch-the-Pills-pdf

Essential Oils Pocket Reference - Fifth Edition https://www.scribd.com/document/326869704/Essential-Oils-Pocket-Reference-Fifth-Edition

Essential Oils Desk Reference https://www.scribd.com/document/394438749/Essential-Oils-Desk-Reference

Essential Oils A Handbook For Aromatherapy Practice https://www.scribd.com/document/343495031/Essential-Oils-a-Handbook-for-Aromatherapy-Practice

The best ones are hardcopy only.

Best herbalists are local, do foraging and distilling themselves. In EO business there are a lot of scams (esp. all pyramid schemes like Young Living). Just buy from oldest known companies that are 100% pure, undiluted, 100% organic or wild-crafted AND with full chromatographic analyses available and steam distillation methods.

Here's one good herbalist to get you started (have used them, product quality is high):

https://mountainroseherbs.com/