Welcome to Frog Forum.
They are not good swimmers so a deep water source is out of the question. You would be better off if you just had a shallow water dish because its much easier to clean and maintain. Coconut Fiber for substrate(not husk) Live plants are ok as long as you choose safe plants like Pathos and Bromeliads. Of course they can be harmful if accidentally eaten so try not to feed the frog close to the plants. Basically not directly in the frogs bite path . A 20. gallon is too large even for an adult. It can be done.but they become stressed very easily by large spaces. n adult male can live his entire life in a 5 gallon tank where as a female gets larger she will need a 10 gallon. Babies and juveniles should be kept in medium or large critter keepers until they are large enough to be moved into larger enclosures. These stages in their life require a lot of food above. nutrition so a smaller home means that there is less room for the prey to escape the frog. Tong feeding is best though.
Place a UGH(Under Tank Heater) on one side of the tank on the actual side just above the top level of the substrate. The water dish should be on the opposite end of the tank creating a warmer side and a cooler side.
Climate needs to be maintained consistantly. 80° to 82° for babies and juveniles during the day and 80° to 85° for adults. night Time temp should be 75° to 79°, but you'll want to hover around 78°. Humidity should be maintained at 80% and can go as low as 75% and even 70% at times, but you'll want to stay at the ideal level.
Combine a UTH with incandescent lighting to produce extra heat to warm the ambient air within the enclosure. Use either a Fluker's 5.5" Clamp lamp with dimmer switch or the 8.5" Clamp lamp with dimmer switch. The dimmer switch allows you to dial in how much heat and light is produced by the bulb. Use a spot light style heat bulb for day time with a concentrated beam because you don't have to dial them up high to produce the necessary heat, but since you want to go with live plants you'll need Full Spectrum Daylight bulbs. Night Time bulbs should be either infrared or moonlight blue. These don't affect their day night cycle.
As for the day/night cycle it needs to be 12 hours of day and 12 of night. You can buy a timer and set the day lights to turn on at 8:00 am and go off and turn the night lights on at 8:00 pm.
please note that you cannot use daylight spotlight bulbs or any type of basil g bulb with Albino Pacman Frogs because their eyes and skin are extra sensitive so you won't be able to use live plants possibly do to not being able to provide the needed lighting. You can still use an infrared bulb or moonlight blue bulb with them though.
Hope this gets you started.