If it's kept at normal room temperature, it will probably take about a week or so. With active heating and dehumidification, it can certainly go faster.
It depends on how moist the lumber has become and how dry you want it. Spruce 50x100 mm that has been moistened up to 25% and is placed on spacers indoors in a room climate (40% RH) takes 12-14 days to reach 15%. In a month, the lumber reaches 10%, so it doesn't happen as quickly as one might think. More heat and some ventilation speeds up the process, as Bob the builder writes. However, be cautious about bringing in too much wet lumber if you can't ensure warmth and good ventilation, otherwise it can easily become very moist indoors, which can cause new problems, and the lumber will dry much more slowly. At 20 degrees and 60% RH, the same drying takes over 3-4 weeks.