Bottlefeeding from breastfeed

Hello mga mommy, Ebf kami ni baby since day 1. ‘M going back to work by April and we decided i-mix feed sya at para masanay narin sa bottle as early as now. Pano ang ginawa nyong transition? Ayaw kasi nya isubo dede kahit na breastmilk un laman, marami muna matatapon bago nya tuluyang dedehin. Or talagang iiyak pa sya so ending hindi ko matitiis, sakin ulit sya dedede. Any tips po? Thank you in advance!