How are the 5’ and 3’ ends tagged?

Tagging on the 5' end is based on Lexogen´s proprietary Cap Dependent Linker Ligation (CDLL) technology. After reverse transcription and generation of a double-stranded RNA : cDNA hybrid, an adapter with a 5' C overhang facilitates atypical base-pairing with the inverted G of the cap structure. Ligation takes place using a double-strand specific ligase, by ligating the 3' end of the double-stranded Cap linker to the 3' end of the cDNA.
Tagging of the 3' end of the mRNA takes place during the reverse transcription through the use of oligo(dT) priming.