掀 implies lifting something from one edge, like flipping a page or lifting a lid. It's different from 揭 (jiē), which is more about peeling off. 掀桌子 (xiān zhuōzi, 'flip the table') is slang for losing your temper dramatically.
Left hand radical — three strokes for the side-form of 手. Indexes 掀 in the manual-action family with 拉 to pull, 推 to push, 抬 to lift up, 揭 to peel back. Anchors the meaning: lifting a cover, turning over a sheet, or stirring up a wave are all done with the hand.
Right 欣 supplies the sound — xīn drifting to xiān with tone shift. 欣 itself is built from 斤 (axe) plus 欠 (yawning mouth) and means 'pleased.' Carries no joy meaning here, but learners can hook the action of 'lifting the lid' onto a small spark of delight at what's revealed.