Thank you for the opportunity to help you with your question!
Count the number of protons and electrons. If there are more protons than electron, then the atom has a POSITIVE charge (+). If there are more electrons than protons, then the atom has a NEGATIVE charge (-).
For example. If an atom has 2 more protons than electrons, you write the symbol of the atom from the Periodic Table then write a +2 next to it.
Please let me know if you need any clarification. I'm always happy to answer your questions.