Set a target allocation per exchange (e.g. BTC 50% · ETH 20% · USDT 30%) — targets total 100%. USDT is a first-class row (your settling currency); it auto-fills to the remainder. Nexus values your live holdings and trades to hit those weights — sell overweight → USDT, buy underweight ← USDT. Set an exchange to Rebalance mode so it's driven by targets and ignores TradingView signals. Rebalancing is manual for now — press Rebalance now; it respects the global Dry-run switch (dry = preview only). Automatic (drift/schedule) triggering comes next.