You can get ready built PCBs with the TP4056 already fitted, I bought 10 of them for £2.50 delivered.
One key factor is choosing the charge current, the PCBs mentioned above will charge at circa 500mA to 1000mA, way too much for small LiPos, so you need to change the charge limit resistor to reduce the current to a safe level for the chosen battery.
But charging is only part of the problem, you need some way of ensuring that the project turns off when the battery drops to circa 3V, go much lower and the battery can be damadged and be dangerous.
Given the risks associated with Lithium batteries, building a Lithium charger out of parts is best left for those that know enough about it that they dont have to ask questions.