After completing an initial, rough transcription, you need to go back and add symbols to best represent your multimodal data in text form. In Conversation Analysis (CA), the most standard conventions are those developed by Gail Jefferson (e.g. 2004, see reference in the resource section).
When adding symbols to your transcript, you need to think carefully about the level of detail you want to include, including whether you will add symbols to represent multimodal and plurilingual phenomena. The tutorials by Antaki (2002) and Schegloff (n.d.), as well as the articles by Mondada (2008) and Nussbaum (2006, see reference in the resource section), should help you make some decisions in this regard.