How should I care for Indoor houseplants? I don't have a green thumb.

Yes,as a matter of fact.Even those without a green thumbb can grow plants. Start with easier maintenance plants....Snake,Dracaena,Pothos,Peace lily,chinese evergreen.once you the the handle on the watering etc.Try other plants.Watch lighting and water conditions and use tepid water.Plants generally do not need water until the top soil feels dry to the touch. Another trick is to insert a pencil in the soil and when you pull it out the if the soil feels dry it is thirsty.Never let plants sit in water either.

Oh dear! How about starting with one plant and adding over time till you get the hang of it? Janet provided excellent suggestions! Another idea would be an African Violet. They do not like bright, hot, harsh sunlight, so if they are in a West or South facing window, make sure it is filtered light. Since I am in a hot, dry, dusty climate, mine do best in a north or east room with filtered light. They get watered from the bottom. Generally once a week is enough. Sit in a shallow dish with some water and let it "drink it up" - if it sucks up all the water, give it a bit more. Wishing you much success! 🌱

Oh and I can't grow orchids, bonsai or boston ferns, my climate is just not well suited for those plants - or I just can't get them to grow! So do not feel bad!

I too have a brown thumb. Research plants that grow in water. No potting soil to buy and you can't over-water them!