I had a couple of questions in going through the basics of vedic astrology
(1) When trying to read what does 1st lord in 2nd house mean, do we look at the Rasi Chart or the Bhava chart?
(2) Similarly, if I have to look for say planets in houses eg., Mars in Taurus, would I look at the Rasi chart or the Bhava chart?
I can see in the Bhava chart that some of the planets have moved houses and signs....hence this confusion.
Astrology, unfortunately, is riddled with such confusing items. If you seek opinions, there would be many since that is the nature of the beast, metaphorically stated! The best way is to look at charts where the planetary shift or relocation occurs (avoid planets too close to a sandhi between rashis, such as a planet at 29.30 of leo for example, because then you would be fighting with two variables! Then use what you have learned as fundamentals in jyotish (remembering that if you apply yourself this collection will or should keep growing!). See if physical and other attributes (as per fundamentals) are fitting more with whole sign or bhavas or a mix of the two. The final answer will not pop into your consciousness suddenly but over time you will be seeing a pattern and that is the only way to reduce confusion if not eliminate it entirely. I say that, because, when it seems to be eliminated entirely, you will be running into a nativity where the pattern does not fit and the head-scratching will begin. But by then your learning would have progressed some more than the time before!
A 'processed food package' answer would be that a planet expresses (or as I maintain, indicates) more confidently and firmly if the sector remains the same by whole sign as well as bhava (you will find at times that there will be differences in positions between Sripati system and equal house divisions as well). If it shows up in different sectors (rashi vs bhava) then the energies represented (and attributes) would tend to be scattered. As you study and come to grips with timings (dasa and transits for starters), the correlation between sector positionings and events etc will further provide confirmation and verification. Going just by attributes (mars in first so an angry person or over energetic) may not be the ideal way to go, though does provide a good starting point. And always do this against the backdrop of which rashi the planet is in! At times it may feel almost as if you are working with a 3-D jig-saw puzzle where some pieces fit perfectly but others do not, hence the importance to view the matrix as an interacting whole!
Your second question is simpler! Mars in Taurus remains mars in Taurus whether it shifts to the sector (in bhava chart) where the cusp belongs to Aries or Gemini.
Regards,
Rohiniranjan