Your D9 planets, overlaid on your D1 chart

Take each planet's D9 (Navamsa) sign and overlay it on your D1 lagna. Whichever D1 house that D9-sign becomes is the planet's RTN house — the additional house theme it activates during its mahadasha and antardashas. So if your D9 Saturn sits in Aries and Aries is your 5th house, Saturn's dasha gives you 5th-house results (children, romance, speculation, intelligence) alongside whatever its natal D1 placement promises.